Thermal cell



March 17, 1925.

' C. NIELSEN, JR

THERMAL CELL Filed Oct. 24, 1924 ill Patented Mar. 17, 1925.

UNITED STATES CHRISTIAN NIELSEN, JR, 015 RIVER FOREST, ILLINOIS.

THERMAL CELL.

Application filed October 24, 1924'. Serial No. 745,730.

To all whom it may concern:

Be it known that I, CHRISTIAN NIELSEN, Jr., a citizen of the United States, and a resident of River Forest, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Thermal Cells; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being bad to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

This invention relates to improvements in thermal cells for giving movement to external mechanism, as for instance, for operating the member of a switch to 0 en and close a circuit, or for mechanical y operating other devices or mechanisms, and the objects of the invention are to reinforce and protect the joint which joins or connects the elements of the cell, to make the cell gas-tight and to increase its working range and its ruggedness and durability.

To these ends the flexible, disc-like side walls of the cell are so joined at their marginal ortions that radial stress on the metal of said walls, due to expansion and contraction of the volatile medium in the chamber of the cell, is transmitted to a reinforcing and connecting element between the marginal portions of said walls in such a way that such stresses are not carried over to the soldered joint by which overlapping portions of the disc-like walls are connected together, thus protecting the soldered joint from rupture, due to such stresses Another object of the invention is to produce a cell of this character in which the connection between the discs has the form of a rugged ring over which the peripheral margins of'the discs are lapped, and lapped one over the other, so that, in addition to protecting the solder or other joint, the cell is greatly reinforced at its periphery to withstand external bruises and pressure.

A. further object of the invention is to provide a novel annular member to join and reinforce the peripheries of the cell walls.

Another object of the invention is to so construct the elements of the cell as to greatly amplify the assembly thereof and to reduce the assembly cost.

Other objects of the invention are to further improve and simplify cell structures; and the invention consists in the elements and combination of elements shown in the drawings, described in the specification, and pointed out in the appended claims.

Reference herein to soldered joints is intended generically to mean any joint in which overlapping parts are bonded together in a manner to produce between parts a non-leaking connection and is therefore 29 be taken as illustrative and not limita- Figure 1 is a plan View ofa thermostatic cell embodying my invention.

Figure 2 is an enlarged radial section of an edge of the cell, in the process of assembling and constructing it.

Fi ure 3 is a similar view of the edge of a finished cell.

Figure 4 is an enlarged elevation, partly broken away, of the reinforcing ring over which the peripheral edges of the cell discs are joined. 7

I will now describe a thermal cell which shows one embodiment of my invention and whlch illustrates the principle thereof, but it is to be understood that the invention is not limited to the exact details shown, except as imposed by the prior art, it being the intent to claim all of inherent novelty shown in the drawings and described in the specification.

As shown in said drawings, 10, 10 designate flat sheet metal discs which constitute the side walls of the cell, and 11 designates the edge reinforcing ring of the cell that is interposed between and is interlocked to the marginal parts of said discs. The said discs 10 can be made of semi-hardened copper stock, or like material and are formed at their margins toproduce inwardly turned flanges 12, 13 that are. adapted to lap one over the other while being assembled, and when set or fixed in place against the periphery of said ring. Preferably, the ring 11 is made of softer copper or like stock, it being hardened in the forming or rolling process.

The transverse section of the reinforcing ring is shown as of concavo-convex cross section. This cross section is preferred, inasmuch as it furnishes ample peripheral concave space 11' to receive the subsequently rolled-in flanges 12, 13 of the discs 10, and also provides good clearance between the inner convex side of the ring and the discs at or along the lines where the discs approach the higher side margins 14 of the ring to permit free inward movement of the walls upon contraction of the cell.

In forming the flanges 12, 13 on the discs, one of said flanges, 13 as herein shown, is somewhat flared so that it may be readily nested over the other, substantially cylindric flange 12, when the flanged discs are as sembled together, in the manner of two cups, with the flanges overlapping exterior to, and over the periphery of, the interposed or intervening reinforcing ring 11. This arrangement simplifies, and reduces the cost of assembling the parts. The internal diameters of the flanges are such as to fit fairly closely over the higher edges 14 of the ring at the junction between the planes of the discs and the said flanges.

Thereafter, the assembled flanged discs and ring are submitted to a radial rolling pressure between suitable rolls whose peripheries conform generally to the final crosssectional shape of the interlocked disc flanges and ring to produce the interlocking efl'ect shown in Figure 3. Said overlapping parts of the flanges and ring will be rolled under considerable pressure so as to bring the metal of the flanges and of the concave face of the ring into intimate contact throughout the outer concave area of said ring.

After the flanges 12 and 13 have been rolled into the concave periphery of the ring 11. the margin of the cell thus mechanically formed is dipped or rolled in a solder bath, the solder passing into the space between the overlying curved flanges and to an extent between the inner flange and the outer concave face of ,the ring. Ordinarily, however, the film 15 of solder which enters the space between the curved faces of the two flanges will constitute an eflicient bond to reliably hold the parts together.

Preferably and as herein shown, the discs are provided a distance radially inside the roots of the flanges 12 and 13 with annular depressions or recesses 16 which serve to bring the first flexion of the discs, either under compression or expansion, inwardly beyond the ring. The formation of said annular recesses produce, radially exterior thereto, flat areas 17 that lie substantially in the planes of the central parts of the discs. It will thus be seen that the first'effeet of the flexion of the disc walls of the cell, due to the expansion or contraction of the contained volatile medium, will be to flex the discs at the annular recesses 16, which will occur in the smaller efforts of compression and expansion and that there will be greater flexion radially outwardly along the areas 17 between the recesses 16 and the roots of the disc flanges.

Inasmuch as the stress on the material of the discs, both under expansion and contraction, is a radial tension stress, it will be seen that this stress islocalized along circular lines at the hi her edges 14 of the ring 11' and the ang e of the lateral sides of the ring to the planes of the discs is such that the stressed material of the discs approaches parallelism to the outer or lateral margins of the ring, or those farthest from the deeper portion of its peripheral concavity. Therefore, owing to the interlocking connection between the metal of the discs and thehigher, lateral margins of the ring, normal working stresses of the metal of the discs will not be transmitted to the inwardly rolled, bonded flanges in a man ner to disturb the bonded joint. Therefore, the integrity of the joint is maintained during all normal uses of the cell and the cell is always sealed against fluid leakage.

It will be obvious from an examination of Figure 3 that the ring 11, which is made of considerably heavier gauge than the metal of the discs 10, greatly reinforces the periphery of the cell thus formed, and strengthens the cell structure against pressure in its plane, and that this reinforcement is further increased byreason of the interlocking engagement of the inwardly rolled concave flanges 12 and 13 of the discs against the concave bottom of said ring and about the lateral or higher edges of the ring. 95

I claim as my invention:

1. A thermal cell comprising flexible side members, a peripheral, overlapped bonded joint connecting said members and means at the lateral sides of the overlap to relieve tension on the joint tending to rupture the bond thereat.

2. A thermal cell comprising flexible side members and a reinforcing and connecting ring between the marginal parts thereof, 105 the margins of said members being flanged and overlapped at their flanged parts and joined and embedded at their overlapped flanges radially within the outermost peripheral part of said ring.

3. A thermal cell comprising flexible side discs and a reinforcing and connecting ring, the margins of said discs being lapped one on the other and being bonded at their overlapped parts and, said ring being periph- 115 erally recessed to receive the overlapped bonded parts of said discs.

4. A thermal cell comprising flexible side discs and a reinforcing and connecting ring of concavo-convex cross section, said discs 12 being overlapped and pressed into the outwardly facing, concave periphery of said ring and bonded at their overlapped portions between the lateral sides of said ring.

5. A thermal cell comprising flexible side discs and a reinforcing and connecting ring having a peripheral recess, the marginal parts of said discs being interlocked to annular shoulders at the lateral sides of sald recess and extending beyond said shoulders and joined at their overlapped parts and clearancebetween the lateral sides of the there pressed within saidrecess. rin and said walls for negative flexion of 10 6. In a thermal cell a reinforcing and consai walls. necting ring provided with an exterlor an- In witnesswhereof that I claim the fore- 5 nular recess to receive wholly therewithin going as myinvention, I hereunto append the overlapped margins of the side walls of my signature this 14th day of October, 1924. the cell, and vconvexly curved on its inner side to afiord at the lateral side of the ring 7 CHRISTIAN NIELSEN, JR. 

